/*
 ***************************************************************************************
 *  Copyright (C) 2006 EsperTech, Inc. All rights reserved.                            *
 *  http://www.espertech.com/esper                                                     *
 *  http://www.espertech.com                                                           *
 *  ---------------------------------------------------------------------------------- *
 *  The software in this package is published under the terms of the GPL license       *
 *  a copy of which has been included with this distribution in the license.txt file.  *
 ***************************************************************************************
 */
package com.espertech.esper.common.internal.epl.expression.visitor;

import com.espertech.esper.common.internal.epl.expression.core.ExprNode;

/**
 * Visitor interface for use with expression node trees.
 */
public interface ExprNodeVisitor {
    /**
     * Allows visitor to indicate whether to visit a given node.
     * Implicitly if a visitor doesn't visit a node it would also not visit any descendent child nodes of that node.
     *
     * @param exprNode is the node in questions
     * @return true if the visitor wants to visit the child node (next call is visit), or false to skip child
     */
    public boolean isVisit(ExprNode exprNode);

    /**
     * Visit the given expression node.
     *
     * @param exprNode is the expression node to visit
     */
    public void visit(ExprNode exprNode);

    default boolean isWalkDeclExprParam() {
        return true;
    }
}
